Per comment #24 above, I don't believe libcprov-javapdf is currently installable, but it worked for me after replacing the first line with
apt install libbcprov-java -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1764450 Title: [needs-packaging] pdftk missing in 18.04 (bionic) and later releases To manage notifications about this bug go to: https://bugs.launchpad.net/pdftk/+bug/1764450/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
